The present invention concerns an actuator for moving a moveable furniture part. The actuator includes at least one moveably mounted actuating member for moving the moveable furniture part, a spring device for applying a force to the actuating member, and an adjusting device by which a force of the spring device, that acts on the actuating member, is adjustable. The adjusting device has a threaded portion and a screw nut mounted displaceably between two end positions, and the force of the spring device, that acts on the actuating member, is adjustable by displacement of the screw nut along the threaded portion.
In addition, the invention concerns an arrangement comprising a moveable furniture part which is mounted moveably by way of an actuator of the kind to be described.
DE 1 584 088 B1 and DE 1 191 257 B each disclose hinges with a compression spring for compensating for the weight of chest freezer lids, wherein the force of the compression spring is adjustable by rotation of a guide tube. Mounted to that guide tube is a plate against which the compression spring is supported with an end. The guide tube has a male thread which is in threaded engagement with a rocker arm bearing against a stationary hinge part.
An actuator in the form of a so-called flap support is described, for example, in DE 100 19 337 A1. That flap support includes two arm portions which are hingedly connected together, and a flap-side arm portion is subjected to the force of a compression spring in the opening direction. Provided for adjusting the force exerted on the flap is an adjusting device which includes a displaceable threaded bolt and a threaded nut in threaded engagement with the threaded bolt.
In the case of adjusting devices having a screw nut mounted displaceably along a threaded portion, a problem which frequently occurs is that the screw nut jams when reaching an end position with a counterpart abutment (for example with an underside of a screw head). Once such jamming occurs between the displaceable screw nut and the counterpart abutment, the jamming can only be released by an increased application of manual force. In addition, release of the jamming is made difficult by the force of the acting spring device, because a person has to release the jamming against the force of the spring device by the application of an increased amount of force.